I've looked at loads of SIBs to replace the one I sold a couple of years ago. Zodiac make a very good SIB, although pricey. The "air" floors that Zodiac and others do are superb. I would only consider components that float - ie eliminate aluminium or GRP floors (oars?) etc, and only consider "air" or wooden floors. Imagie if you ever want to transport the SIB in your RIB and have to assemble it at sea...
Lodestar also make a superb SIB - have a look at
http://www.lodestardirect.co.uk Do beware of weight when considering SIBs - some of the cheap ones are very heavy and difficult to handle.